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Topic Review (Newest First)

06-30-2007 08:32 AM

ccb

Quote:

Originally Posted by jjl

Hi Doc,
This is an immobilizer that operates as follows.
- Turn it on by pressing the switch (momentary on button). The DPDT is then supposed to stay activated and disengage the std relay and at the same time powering the led, which flashes.
- To turn it off you hold a magnet infront of the reed switch (hidden behind dash somwhere) and the power returns to the std relay and completes the circuit that has been immobilised. The led is also turned off.

The std relay is no drama, I just could not make sense of the crappy diagram, mainly for the terminals for the DPDT relay.

The idea is that even if someone steals your keys, they cannot bypass the kill switch, except by using tow truck.

You would have to reverse the reed switch and the push button for your diagram to work this way. The bigest problem is your relay is energized the time you have things "embobilized". a locking relay would be cool. power pulse to open and a power pulse to close. May be Doc can help.

06-30-2007 02:23 AM

docvette

Doc here,

Here is a basic diagram for a defeat system..

The wire from the relay coil should actually go to the exsisting Ignition wire strike the wire from the battery to the 1 amp fuse..it goes to the Coil + wire that powers the ignition coil now..Sorry...my bad..crummy schematic software..BUT the rest remains the same..

The relay is a standard Bosch relay, you can get at ANY autoparts store for $4 fazools..the numbers on the wires in the schematic conform to the bottom of the standard bosch relay.

The Fuse is 1 amp , for the relay coil only.

The fuse link is 50 amp (can be a maxi fuse, and inline holder if desired) , it supports the draw of the coil. The 10 gauge wire is an upgrade..It will allow more current to the coil and the ignition should run better..

The Hidden switch may be as creative as you want..I usually install one of these headphone type jacks (Female side) around the CD player in the dash (so it looks like it belongs there..) The Plug (Male side) is soldered together (ring to tip) under the sleeve which unscrews, so that it completes the circuit when it is plugged in to the dash JACK..

When The PLUG is pulled out, the relay De~energizes, and the contacts open, cutting power to the coil..Ergo, the engine won't run..just take it with you when you leave the vehicle...You can chose any of these Styles from your local rat shak or fry's..JUST be sure the headphone JACK is isolated off ground , the grounded type will short.

You can use any other combination of hidden switches you want also, hiding them in "Creative " spots..like inside the gas flap, In the glove box or console (first place a crook looks..) under the dash..BEHIND the rear view mirror, Get as creative as you want..

If you want to be more slick, you can get a Mercury type switch,

Mount it on your sun visor, so that when you adjust it all the way up..it is off.."No Start", adjust it so with a little downward adjustment (not enough to mess with your field of vision) It is "ON " and runs..you have to be careful with this though..bumps can be a bad thing if adjusted too close.

IF you have a CD RADIO Player..you can substitute the switch , and don't use the wire behind it coming from the Ignition "ON" , and isolate the "Power Antenna " wire off the back of the player (usually the blue wire)

In this configuration, the key MUST be on..(to turn the radio on) AND the radio must be on (so that there is power to the antenna) This has drawbacks..

the player must be on at all times while driving and you must use "mute" if you don't want to hear it..When you leave the car..take the detachable face plate with you and the car can not be started..Again..you can get as creative as you want..

You need two parameters in order for this to operate..you need the "jumper plug " installed AND you must have the Key ON , in order to get power to the coil..with only one element, or the other, you can crank until the battery goes dead, it won't start.

IF you REALLY want to get creative..run a 10 gauge wire from the 87a terminal, to the horn..If a crook tries to "jump" power to the + side of the coil..the horn goes off and stays on until the jumper is removed..(scares the humus right outta them..)

All those switch/location options are open to you..just pick one , or go with the basic drawing above..all are effective as a first line of defense.

many other options exist also.

Doc

06-30-2007 12:40 AM

jjl

Hi Doc,
I am interested in your diagram if you can post it or send it to me. All I am after is some form of protection for the car. I know pro thieves do not have problems, but there are more idiots around that like pinching cars and even simple protection is a good start - sometimes.
Nothing stops a flat bed truck.
Jeremy

06-29-2007 05:29 PM

docvette

Doc here,

Immobilizer , Keys or not..

Any thief can simply jump battery power to the BATT terminal on your car (Or in most cases, jump a wire between the IGN and BATT terminals at the fuse box) and a jumper at the "S" and "I" terminals..and he's off and running! takes 30 seconds for two to do.

I can give you a relay operated system with several options that is easier that that one if you like..BUT remember: Nothing is foolproof..whatever the mind of man can conceive, the mind of man can defeat..

Doc

06-29-2007 12:09 AM

jjl

Hi Doc,
This is an immobilizer that operates as follows.
- Turn it on by pressing the switch (momentary on button). The DPDT is then supposed to stay activated and disengage the std relay and at the same time powering the led, which flashes.
- To turn it off you hold a magnet infront of the reed switch (hidden behind dash somwhere) and the power returns to the std relay and completes the circuit that has been immobilised. The led is also turned off.

The std relay is no drama, I just could not make sense of the crappy diagram, mainly for the terminals for the DPDT relay.

The idea is that even if someone steals your keys, they cannot bypass the kill switch, except by using tow truck.

06-28-2007 05:58 PM

docvette

Doc here,

First of all...

That is a REALLY crappy diagram..

The schematic Symbols for relays, Etc..are not even correct...hooking it up without a continuity check will be a crapshoot..

What are you trying to do?

I probably can give you a much better circuit.

Doc

06-28-2007 03:28 PM

starnest

NO is Normally Open
NC is Normally Closed
In a DPDT (Double Pole - Double Throw) switch or relay
double pole means two relay circuits, double throw means each relay circuit switches between two contacts, one contact is closed(NC) and the other is open(NO) when the relay is de-energized. Energize the relay and the closed contact will open and the open contact will close.

06-28-2007 02:33 PM

msherrow

I will try...the coil connections are the 12v supply going into the top and the wire through the reed switch. The wire from the DPDT relay to the std relay and the wire to earth are also the coil connections for the std relay. You will need to read out the connections to see which is input or output with pwr applied to coil. You should have pwr to flashing led with no earth ground applied to coil, and pwr removed when coil grounded. With coil grounded pwr is sent to std relay to energize it and close circuit. Normally closed push button is for locking/unlocking of DPDT relay. Sooo inputs are 12v and jumper from reed switch wire. Outputs are normally closed switch to ground and input to std relay with relay energized and to flashing led with relay deenergized. Would be easier if I could remember what NO and NC stood for
Mike

06-28-2007 02:20 PM

ccb

this diagram

12 volt power to DPDT relay coil to magnet reed switch to ground. One NO contact; coil ground to NC push-button to ground. One NO contact; 12 v power to HD relay to ground. One NC 12 V power to LED to ground.

Using a magnet to close the reed switch energizes the DPDT relay, energizing the HD relay opening the circuit you want to control, it also switches the LED off. The circuit through the push button keeps the relay 'pulled in'. Push the button opens the circuit holding the relay allowing it to 'drop out' this lights the LED and allows the HD relay to de-energize and close the circuit you are controlling.

06-28-2007 04:08 AM

jjl

Can someone please make sense of this diagram?

I would like to use this circuit diagram for an immobiliser. The only problem is my electronic skills are sfa and I cannot make sense of the relay wiring.
Can anyone please help here by telling me which terminal is which on the DPDT relay and which is which on the normal relay. The DPDT relay I have has two NO and two NC terminals and two others for Coil, and the std relay has the typical 30 87 etc terminals. Trouble is I do not know which one is which in the wiring diagram.
THanks for any help.